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Abstract STABILITY AND CHANGE IN THE INDIAN RIVER AREA BRYOZOAN FAUNA OVER A 24- YEAR PERIOD Judith E. Winston Long-term studies are essential to document changes in marine communities over time. Yet most research projects are limited to a very short time period, the length of a single grant or dissertation period. A monthly survey of the Indian River Area bryozoan fauna carried out in 1974-1975 as part of a postdoctoral fellowship at the Smithsonian Marine Station was published in 1982. The existence of this baseline work made it possible to return to resurvey some of the same areas to determine whether or not the bryozoan communities at some of the sites in the original study had changed or stayed the same. Results showed that most of the species that were abundant at a site were still occurred at that site 24 years later, indicating a high degree of stability. However, there were some important changes. Temperate species such as Hippoporina verrilli, Cryptosula pallasiana and Bugula stolonifera, which had been abundant in 1974 were rare or absent, in 1998. They were replaced by Caribbean species, such as Exechonella antillaea and Caulibugula armata. Although local seawater temperatures during the time period were not available, the Fort Pierce air temperature records indicated that despite the year to year variability in both minimum and maximum temperatures over the seasons, mean winter air temperatures maintained a slow increase from 1974-1999.
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